50 terms

Chapter 3: How does the body communicate internally?

The brain coordinates the body's two communications systems, the nervous system and the endocrine system, which use similar chemical processes to communicate with targets throughout the body
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Terms in this set (...)

neuron
cell specialized to receive, process, and transmit info to other cells; nerve cells
Sensory neurons
afferent; nerve cell that carries messages from sense receptors toward the CNS
motor neurons
efferent; nerve cell that carries messages away from the CNS toward the muscles and glands
interneurons
a nerve cell that relays messages between nerve cells, esp in the brain and spinal cord
dendrites
nerve cell receiver; branched fiber that extends outward from the main cell body and carries info into the neuron; can undergo subtle modifications as we learn
soma
cell body; part of cells containing the nucleus and life-support machinery; assesses all messages the cell receives from other cells or dendrites
excitatory
messages that tell a neuron to fire
inhibitory
messages that tell a neuron not to fire
axon
extended fiber that conducts info from soma to terminal buttons; electrical action potential travels down
ions
charged chemicals from which an exon gets its electrical energy
resting potential
electrical charge of the axon in its negative, inactive state; neuron is ready to fire
action potential
nerve impulse caused by a change in the electrical charge across the cell membrane of the axon; charge becomes positive as positive ions rush into cell; progresses down axon
all-or-none principle
an action potential in the axon occurs either full blown or not at all
synapse
microscopic gap that serves as a communications link between neurons; acts as electrical insulator
terminal buttons
bulblike structures at the end of the axon; contain neurotransmitters that carry the neuron's message into the synapse
synaptic transmission
electrical message of action potential morphs into a chemical message that easily flows across the synaptic cleft
synaptic vesicle
contains about 5000 neurotransmitter molecules; connects to the presynaptic membrane, releasing neurotransmitter into synapse
neurotransmitter
chemical messengers that relay neural messages across the synapse to attach to receptors in the membrane of the target cell; lock and key process stimulates receiving neuron
reuptake
used neurotransmitters break, return to terminal buttons, and are reassembled; drawn back intact into vesicles; turn down message being transmitted
dopamine
pleasure and reward, voluntary movement; schizophrenia and Parkinson's; cocaine, alcohol, amphetamins
serotonin
sleep, dreaming, mood, pain, aggression, appetite, sexual behavior; Depression, anxiety, OCD; prozac, hallucinogenics
norepinephrine
heart rate, sleep, stress, sexual responsiveness, vigilance, appetite; high blood pressure, depression; tricyclic antidepressants, beta-blockers
ACh
efferent; some learning and memory; muscular disorders, Alzheimer's; nicotine, botox, curare
GABA
inhibitory; anxiety, epilepsy; barbiturates, tranquilizers, alcohol
Glutamate
excitatory, learning and memory; can cause brain damage after stroke; PCP
endorphins
pleasurable sensations, pain control; low levels from opiate addiction; opiates
plasticity
nervous system's ability to adapt or change as the result of experience; may help with nervous system's ability to adapt to physical damage; allows brain to be restructured by experience; ex sexual abuse victims overreact; blind Braille reader has more brain area to index finger
glial cells
cells that bind neurons together; provide insulating myelin sheath of axon for some neurons and facilitates electrical impulse
Nervous System
entire network of neurons in the body
CNS
brain and spinal cord; body's command center; decisions, functions, behaviors; spinal cord handles reflexes
reflex
simple, unlearned response triggered by stimuli
PNS
all parts of the nervous system lying outside the CNS; connects CNS with the rest of the body through sensory and motor axons (nerves)
somatic
brain's communications link with the outside world; carries sensory info to the CNS and sends voluntary messages to the skeletal muscles
autonomic
sends communications between the CNS and the internal organs and glands
sympathetic
sends messages to internal organs and glands that help body respond to stressful situations; fight or flight
parasympathetic
monitors routine operations of the internal organs and returns body to calmer functioning after arousal by the sympathetic
endocrine system
hormone system; body's chemical messenger system; release hormones into bloodstream; usually works with parasympathetic but shifts to support sympathetic in crisis
hormone
chemical messenger used by the endocrine system; influence behaviors, emotions, and body functions
pituitary gland
"master gland" ; base of the brain; keeps endocrine responses under control; receives orders from the hypothalamus
anterior pituitary
ovaries and testes; breast milk; metabolism; stress responses
posterior pituitary
water conservation; breast milk; uterus contractions
thyroid
metabolism; physical growth and development
parathyroid
calcium levels
pancreas
glucose metabolism
adrenal glands
fight or flight; metabolism; sex drive esp in women
ovaries
female sex characteristics; produce eggs
testes
male sex characteristics; sperm production; sex drive in men
agonist
enhance or mimic neurotransmitters; nicotine for ACh
antagonist
dampen or inhibit effects of neurotransmitters; curare and botox for ACh
neural pathway
bundle of nerve cells that follow generally the same route and employ the same neurotransmitter; allows drug to target specific parts of the brain but also causes side effects; Prozac for serotonin